A rectangle is $8$ units long. The rectangle is also $1$ unit wide. What is its perimeter?
$8\text{ }$ $1\text{ }$ The perimeter is the total length of all the sides of the shape added together. Add up the lengths of the sides: $ \text{perimeter} = {1} + {8} + {1} + {8} $ $ \text{perimeter} = 18\text{ } $